/// background_sky_startup()

background_image_sphere_vbuffer = null
background_image_cube_vbuffer = null
background_image_cube_mapped_vbuffer = null

background_fog_texture = texture_sprite(spr_fog)
background_fog_vbuffer = null

background_sky_stars_texture = texture_sprite(spr_stars)
background_sky_stars_vbuffer = null
background_sky_sun_vbuffer = null
background_sky_moon_vbuffer = null
background_sky_clouds_vbuffer = null
